Measure of Microglial Activation in the Brain of Parkinson Disease Patients With PET

There is accumulating evidence suggesting that inflammatory processes, through microglial activation, would play a key role in the neurodegenerative process of Parkinson's disease (PD). It is considered that microglial activation would be part of self-propelling cycle of neuroinflammation that fuels the progressive dopaminergic neurodegeneration. It is however hard to evidence microglial activation in vivo, especially in the substantia nigra: first, the investigators need very high resolution imaging tools and then, the only ligand available to date, 11C-PK11195, has a low sensitivity and specificity and provided heterogeneous results. 18F-DPA-714 is a new PET ligand which labels microglial cells. The investigators aim to explore the topography and intensity of microglial activation in several different groups of PD patients: 1) de novo, drug-naïve subjects (n = 6); 2) non-fluctuating treated patients ("honeymoon") (n = 10); 3) advanced drug-responsive patients motor fluctuations (wearing-off or dyskinesia) (n = 6); 4) patients with LRRK2 gene mutation (n = 6); and 5) related to healthy patients carriers of the mutation LRRK2(n = 6). PET imaging will be performed with a new generation tomography having a very high resolution. This study might reveal significant neuroinflammatory process in the midbrain of PD patients and will determine if such process is present in both sporadic and genetic forms of PD. The results of this study might provide a new biomarker of disease pathological progression and help as identifying subjects who might most benefit from a specific anti-inflammatory drug.